Protective conditioning of the brain: expressway or roadblock?

The effect of anaesthetic exposure in presurgical period on delayed cerebral ischaemia and neurological outcome in patients with aneurysmal subarachnoid haemorrhage undergoing clipping of aneurysm: A retrospective analysis

Background and Aims:

Delayed cerebral ischaemia is one of the major contributors to morbidity in aneurysmal subarachnoid haemorrhage (aSAH). General anaesthesia (GA) in the presurgical period may have a preconditioning effect. The primary aim was to assess the effect of preoperative exposure to GA during digital subtraction angiography (DSA) on neurological outcome in patients presenting with aSAH.

Methods:

After Ethical Committee approval, we conducted a retrospective analysis of the data of patients with aSAH treated surgically. Patients, admitted to neurosurgical ICU (June 2014 and December 2017) with a computed tomography (CT) diagnosis of aSAH and underwent DSA, were included. DSA, done with or without exposure to a general anaesthetic, was classified to GA group and LA group, respectively. Propensity score matching was done on the baseline variables. Appropriate statistical methods were applied.

Results:

Of the 278 patients, 116 (41.7%) patients had received GA during DSA. Propensity matching yielded 114 (57 in each group) matched patients. In a logistic regression model, the odds ratio (OR) for poor outcome at discharge in GA group as compared to LA group was 4.4 (CI: 2.7–7.4), P = 0.001, whereas, in the matched data, the OR for poor outcome at discharge in GA group as compared to LA group was 1.2 (CI: 0.6–2.6), P = 0.57.

Conclusion:

The presurgical exposure to GA did not offer any neuroprotection and the odds of poor outcome were higher compare to non-exposure to GA group.

A Role of Endogenous Progesterone in Stroke Cerebroprotection Revealed by the Neural-Specific Deletion of Its Intracellular Receptors

Treatment with progesterone protects the male and female brain against damage after middle cerebral artery occlusion (MCAO). However, in both sexes, the brain contains significant amounts of endogenous progesterone. It is not known whether endogenously produced progesterone enhances the resistance of the brain to ischemic insult. Here, we used steroid profiling by gas chromatography-tandem mass spectrometry (GC-MS/MS) for exploring adaptive and sex-specific changes in brain levels of progesterone and its metabolites after MCAO. We show that, in the male mouse brain, progesterone is mainly metabolized via 5α-reduction leading to 5α-dihydroprogesterone (5α-DHP), also a progesterone receptor (PR) agonist ligand in neural cells, then to 3α,5α-tetrahydroprogesterone (3α,5α-THP). In the female mouse brain, levels of 5α-DHP and 3α,5α-THP are lower and levels of 20α-DHP are higher than in males. After MCAO, levels of progesterone and 5α-DHP are upregulated rapidly to pregnancy-like levels in the male but not in the female brain. To assess whether endogenous progesterone and 5α-DHP contribute to the resistance of neural cells to ischemic damage, we inactivated PR selectively in the CNS. Deletion of PR in the brain reduced its resistance to MCAO, resulting in increased infarct volumes and neurological deficits in both sexes. Importantly, endogenous PR ligands continue to protect the brain of aging mice. These results uncover the unexpected importance of endogenous progesterone and its metabolites in cerebroprotection. They also reveal that the female reproductive hormone progesterone is an endogenous cerebroprotective neurosteroid in both sexes.SIGNIFICANCE STATEMENT The brain responds to injury with protective signaling and has a remarkable capacity to protect itself. We show here that, in response to ischemic stroke, levels of progesterone and its neuroactive metabolite 5α-dihydroprogesterone are upregulated rapidly in the male mouse brain but not in the female brain. An important role of endogenous progesterone in cerebroprotection was demonstrated by the conditional inactivation of its receptor in neural cells. These results show the importance of endogenous progesterone, its metabolites, and neural progesterone receptors in acute cerebroprotection after stroke. This new concept could be exploited therapeutically by taking into account the progesterone status of patients and by supplementing and reinforcing endogenous progesterone signaling for attaining its full cerebroprotective potential.

Pathogenic mechanisms following ischemic stroke

Stroke is the second most common cause of death and the leading cause of disability worldwide. Brain injury following stroke results from a complex series of pathophysiological events including excitotoxicity, oxidative and nitrative stress, inflammation, and apoptosis. Moreover, there is a mechanistic link between brain ischemia, innate and adaptive immune cells, intracranial atherosclerosis, and also the gut microbiota in modifying the cerebral responses to ischemic insult. There are very few treatments for stroke injuries, partly owing to an incomplete understanding of the diverse cellular and molecular changes that occur following ischemic stroke and that are responsible for neuronal death. Experimental discoveries have begun to define the cellular and molecular mechanisms involved in stroke injury, leading to the development of numerous agents that target various injury pathways. In the present article, we review the underlying pathophysiology of ischemic stroke and reveal the intertwined pathways that are promising therapeutic targets.

Novel Treatments in Neuroprotection for Aneurysmal Subarachnoid Hemorrhage

OPINION STATEMENT

New neuroprotective treatments aimed at preventing or minimizing "delayed brain injury" are attractive areas of investigation and hold the potential to have substantial beneficial effects on aneurysmal subarachnoid hemorrhage (aSAH) survivors. The underlying mechanisms for this "delayed brain injury" are multi-factorial and not fully understood. The most ideal treatment strategies would have the potential for a pleotropic effect positively modulating multiple implicated pathophysiological mechanisms at once. My personal management (RFJ) of patients with aneurysmal subarachnoid hemorrhage closely follows those treatment recommendations contained in modern published guidelines. However, over the last 5 years, I have also utilized a novel treatment strategy, originally developed at the University of Maryland, which consists of a 14-day continuous low-dose intravenous heparin infusion (LDIVH) beginning 12 h after securing the ruptured aneurysm. In addition to its well-known anti-coagulant properties, unfractionated heparin has potent anti-inflammatory effects and through multiple mechanisms may favorably modulate the neurotoxic and neuroinflammatory processes prominent in aneurysmal subarachnoid hemorrhage. In my personal series of patients treated with LDIVH, I have found significant preservation of neurocognitive function as measured by the Montreal Cognitive Assessment (MoCA) compared to a control cohort of my patients treated without LDIVH (RFJ unpublished data presented at the 2015 AHA/ASA International Stroke Conference symposium on neuroinflammation in aSAH and in abstract format at the 2015 AANS/CNS Joint Cerebrovascular Section Annual Meeting). It is important for academic physicians involved in the management of these complex patients to continue to explore new treatment options that may be protective against the potentially devastating "delayed brain injury" following cerebral aneurysm rupture. Several of the treatment options included in this review show promise and could be carefully adopted as the level of evidence for each improves. Other proposed neuroprotective treatments like statins and magnesium sulfate were previously thought to be very promising and to varying degrees were adopted at numerous institutions based on somewhat limited human evidence. Recent clinical trials and meta-analysis have shown no benefit for these treatments, and I currently no longer utilize either treatment as prophylaxis in my practice.

Remote ischemic preconditioning in the prevention of ischemic brain damage during intracranial aneurysm treatment (RIPAT): study protocol for a randomized controlled trial

BACKGROUND

The treatment of intracranial aneurysms may be associated with cerebral ischemia. We hypothesize that pre-interventional remote ischemic preconditioning (RIPC) reduces ischemic cerebral tissue damage in patients undergoing elective intracranial aneurysm treatment.

METHODS/DESIGN

This study is a single-center, prospective, randomized, double-blind explorative trial. Patients with an unruptured intracranial aneurysm admitted to Innsbruck Medical University Hospital for coiling or clipping will be consecutively randomized to either the intervention group (= RIPC by inflating an upper extremity blood-pressure cuff for 3 x 5 min to 200 mmHg) or the control group after induction of anesthesia. Participants will be randomized 1:1 to either the preconditioning group or the sham group using a random allocation sequence and block randomization. The precalculated sample size is n = 24 per group. The primary endpoint is the area-under-the-curve concentration of serum biomarkers (S100B, NSE, GFAP, MMP9, MBP, and cellular microparticles) in the first five days after treatment. Secondary endpoints are the number and volume of new ischemic lesions in magnetic resonance imaging and clinical outcome evaluated with the National Institutes of Health Stroke Scale, the modified Rankin Scale, and neuropsychological tests at six and twelve months. All outcome variables will be determined by observers blinded to group allocation. This study was approved by the local institutional Ethics Committee (UN5164), version 3.0 of the study protocol, dated 20 October 2013.

DISCUSSION

This study uses the elective treatment of intracranial aneurysms as a paradigmatic situation to explore the neuroprotective effects of RIPC. If effects are demonstrable in this pilot trial, a larger, prospective phase III trial will be considered.

New horizons for newborn brain protection: enhancing endogenous neuroprotection

Intrapartum-related events are the third leading cause of childhood mortality worldwide and result in one million neurodisabled survivors each year. Infants exposed to a perinatal insult typically present with neonatal encephalopathy (NE). The contribution of pure hypoxia-ischaemia (HI) to NE has been debated; over the last decade, the sensitising effect of inflammation in the aetiology of NE and neurodisability is recognised. Therapeutic hypothermia is standard care for NE in high-income countries; however, its benefit in encephalopathic babies with sepsis or in those born following chorioamnionitis is unclear. It is now recognised that the phases of brain injury extend into a tertiary phase, which lasts for weeks to years after the initial insult and opens up new possibilities for therapy.There has been a recent focus on understanding endogenous neuroprotection and how to boost it or to supplement its effectors therapeutically once damage to the brain has occurred as in NE. In this review, we focus on strategies that can augment the body's own endogenous neuroprotection. We discuss in particular remote ischaemic postconditioning whereby endogenous brain tolerance can be activated through hypoxia/reperfusion stimuli started immediately after the index hypoxic-ischaemic insult. Therapeutic hypothermia, melatonin, erythropoietin and cannabinoids are examples of ways we can supplement the endogenous response to HI to obtain its full neuroprotective potential. Achieving the correct balance of interventions at the correct time in relation to the nature and stage of injury will be a significant challenge in the next decade.

Cerebral Ischemic Preconditioning: the Road So Far…

Cerebral preconditioning constitutes the brain's adaptation to lethal ischemia when first exposed to mild doses of a subtoxic stressor. The phenomenon of preconditioning has been largely studied in the heart, and data from in vivo and in vitro models from past 2-3 decades have provided sufficient evidence that similar machinery exists in the brain as well. Since preconditioning results in a transient protective phenotype labeled as ischemic tolerance, it can open many doors in the medical warfare against stroke, a debilitating cerebrovascular disorder that kills or cripples thousands of people worldwide every year. Preconditioning can be induced by a variety of stimuli from hypoxia to pharmacological anesthetics, and each, in turn, induces tolerance by activating a multitude of proteins, enzymes, receptors, transcription factors, and other biomolecules eventually leading to genomic reprogramming. The intracellular signaling pathways and molecular cascades behind preconditioning are extensively being investigated, and several first-rate papers have come out in the last few years centered on the topic of cerebral ischemic tolerance. However, translating the experimental knowledge into the clinical scaffold still evades practicality and faces several challenges. Of the various preconditioning strategies, remote ischemic preconditioning and pharmacological preconditioning appears to be more clinically relevant for the management of ischemic stroke. In this review, we discuss current developments in the field of cerebral preconditioning and then examine the potential of various preconditioning agents to confer neuroprotection in the brain.

Ischemic conditioning-induced endogenous brain protection: Applications pre-, per- or post-stroke

In the area of brain injury and neurodegenerative diseases, a plethora of experimental and clinical evidence strongly indicates the promise of therapeutically exploiting the endogenous adaptive system at various levels like triggers, mediators and the end-effectors to stimulate and mobilize intrinsic protective capacities against brain injuries. It is believed that ischemic pre-conditioning and post-conditioning are actually the strongest known interventions to stimulate the innate neuroprotective mechanism to prevent or reverse neurodegenerative diseases including stroke and traumatic brain injury. Recently, studies showed the effectiveness of ischemic per-conditioning in some organs. Therefore the term ischemic conditioning, including all interventions applied pre-, per- and post-ischemia, which spans therapeutic windows in 3 time periods, has recently been broadly accepted by scientific communities. In addition, it is extensively acknowledged that ischemia-mediated protection not only affects the neurons but also all the components of the neurovascular network (consisting of neurons, glial cells, vascular endothelial cells, pericytes, smooth muscle cells, and venule/veins). The concept of cerebroprotection has been widely used in place of neuroprotection. Intensive studies on the cellular signaling pathways involved in ischemic conditioning have improved the mechanistic understanding of tolerance to cerebral ischemia. This has added impetus to exploration for potential pharmacologic mimetics, which could possibly induce and maximize inherent protective capacities. However, most of these studies were performed in rodents, and the efficacy of these mimetics remains to be evaluated in human patients. Several classical signaling pathways involving apoptosis, inflammation, or oxidation have been elaborated in the past decades. Newly characterized mechanisms are emerging with the advances in biotechnology and conceptual renewal. In this review we are going to focus on those recently reported methodological and mechanistic discoveries in the realm of ischemic conditioning. Due to the varied time differences of ischemic conditioning in different animal models and clinical trials, it is important to define optimal timing to achieve the best conditioning induced neuroprotection. This brings not only an opportunity in the treatment of stroke, but challenges as well, as data is just becoming available and the procedures are not yet optimized. The purpose of this review is to shed light on exploiting these ischemic conditioning modalities to protect the cerebrovascular system against diverse injuries and neurodegenerative disorders.

An active component of Achyranthes bidentata polypeptides provides neuroprotection through inhibition of mitochondrial-dependent apoptotic pathway in cultured neurons and in animal models of cerebral ischemia

An active component has been isolated by reverse-phase high performance liquid chromatography (HPLC) from Achyranthes bidentata Blume polypeptides that are extracted from Achyranthes bidentata Blume, a Chinese medicinal herb. The active component is called ABPPk based on the order of HPLC elution. In this study, we used in vitro and in vivo experimental models of cerebral ischemia to investigate the possible neuroprotective effect of ABPPk. ABPPk treatment promoted neuronal survival and inhibited neuronal apoptosis in primary cortical neurons exposed to oxygen and glucose deprivation and in rats subjected to transient middle cerebral artery occlusion. The role of ABPPk in protection against ischemia-induced neuronal damage might be mediated by mitochondrial-dependent pathways, including modulation of apoptosis-related gene expression, regulation of mitochondrial dysfunction through restoring mitochondrial membrane potential, reducing release of mitochondrial apoptogenic factors, and inhibiting intracellular ROS production. The neuroprotective effect of ABPPk may suggest the possible use of this agent in the treatment and prevention of cerebral ischemic stroke.

Histone acetylation and CREB binding protein are required for neuronal resistance against ischemic injury

Epigenetic transcriptional regulation by histone acetylation depends on the balance between histone acetyltransferase (HAT) and deacetylase activities (HDAC). Inhibition of HDAC activity provides neuroprotection, indicating that the outcome of cerebral ischemia depends crucially on the acetylation status of histones. In the present study, we characterized the changes in histone acetylation levels in ischemia models of focal cerebral ischemia and identified cAMP-response element binding protein (CREB)–binding protein (CBP) as a crucial factor in the susceptibility of neurons to ischemic stress. Both neuron-specific RNA interference and neurons derived from CBP heterozygous knockout mice showed increased damage after oxygen-glucose deprivation (OGD) in vitro. Furthermore, we demonstrated that ischemic preconditioning by a short (5 min) subthreshold occlusion of the middle cerebral artery (MCA), followed 24 h afterwards by a 30 min occlusion of the MCA, increased histone acetylation levels in vivo. Ischemic preconditioning enhanced CBP recruitment and histone acetylation at the promoter of the neuroprotective gene gelsolin leading to increased gelsolin expression in neurons. Inhibition of CBP's HAT activity attenuated neuronal ischemic preconditioning. Taken together, our findings suggest that the levels of CBP and histone acetylation determine stroke outcome and are crucially associated with the induction of an ischemia-resistant state in neurons.

A versatile tool for the analysis of neuronal survival

To understand the principles that govern mechanisms of neuronal survival or death it is necessary to systematically model these processes. Methods involving overexpression or knockdown of a gene of interest using non-viral transfection of primary neurons can easily be adapted to study cell death pathways in primary neurons. However, common biochemical approaches to measure cell death are insufficient to measure neuronal viability in these systems. To investigate the functional role of genes in cultured neurons, we therefore established a cell-based assay using a cotransfection/cocultivation approach in primary cortical neurons from mouse or rat. Using this method, it is possible to use well-established cell culture models of neuronal damage, and to analyze cell survival in genetically different neurons on a single-cell basis following apoptotic stimuli under identical conditions. The duration of the entire protocol is 10 days. Finally, the method may be applicable to a wide range of damage models, primary cells, and cell lines as well as it can be used for high content screening (HCS) studies and downstream image cytometry.

Do stroke models model stroke?

Stroke is one of the leading causes of death worldwide and the biggest reason for long-term disability. Basic research has formed the modern understanding of stroke pathophysiology, and has revealed important molecular, cellular and systemic mechanisms. However, despite decades of research, most translational stroke trials that aim to introduce basic research findings into clinical treatment strategies - most notably in the field of neuroprotection - have failed. Among other obstacles, poor methodological and statistical standards, negative publication bias, and incomplete preclinical testing have been proposed as 'translational roadblocks'. In this article, we introduce the models commonly used in preclinical stroke research, discuss some of the causes of failed translational success and review potential remedies. We further introduce the concept of modeling 'care' of stroke patients, because current preclinical research models the disorder but does not model care or state-of-the-art clinical testing. Stringent statistical methods and controlled preclinical trials have been suggested to counteract weaknesses in preclinical research. We conclude that preclinical stroke research requires (1) appropriate modeling of the disorder, (2) appropriate modeling of the care of stroke patients and (3) an approach to preclinical testing that is similar to clinical testing, including Phase 3 randomized controlled preclinical trials as necessary additional steps before new therapies enter clinical testing.

A functional role of the cyclin-dependent kinase inhibitor 1 (p21(WAF1/CIP1)) for neuronal preconditioning

Hypoxic preconditioning is thought to rely on gene products regulated by hypoxia-inducible factor (HIF)-1. Here, we show that the HIF-1 target gene cyclin-dependent kinase inhibitor 1, p21(WAF1/CIP1), is essential for neuroprotection by hypoxic/aglycemic or erythropoietin preconditioning using wild-type and p21(WAF1/CIP1)-deficient neurons. Furthermore, overexpression of wild-type p21(WAF1/CIP1) or phospho-mutants significantly increased cell death after hypoxia/aglycemia. Moreover, deferoxamine-induced endogenous tolerance did not involve p21(WAF1/CIP1) expression in cortical neurons. Our data suggest that balanced expression and potentially posttranslational regulation of p21(WAF1/CIP1) is required for hypoxic preconditioning.

Neuroglobin and neuronal cell survival

The balance between neuronal apoptosis and survival sculpts the developing brain and has an important role in neurodegenerative diseases. Thus, the individuation of signals that could modulate the cell death machinery as well as enhance survival in neurons promises to provide multiple points of therapeutic intervention in neurodegenerative diseases. Neuroglobin (NGB), the first nerve globin identified in neuronal tissues of humans, seems to possess a protective role in the brain only after up-regulation. Here, the NGB physiological role in the control of neuronal survival is reviewed. In vitro studies suggested that cytosolic NGB could react very rapidly with cytochrome c released from mitochondria, thus interfering with the intrinsic pathway of apoptosis. Although very suggestive, these data do not explain either the role of NGB up-regulation in neuroprotection or the recently reported NGB localization into mitochondria. Recently, we identified the steroid hormone 17β-estradiol (E2) as an endogenous modulator of NGB levels in neuroblastoma SK-N-BE cell line. Upon E2 stimulation, NGB reallocates mainly into mitochondria where the association with the mitochondrial cytochrome c occurs. Remarkably, E2 treatment before an apoptotic stimulus strongly enhances the NGB:cytochrome c association reducing cytochrome c release into the cytosol. As a consequence, a decrease of caspase-3 activation and, in turn, of the apoptotic cascade activation take place. Besides E2, other compounds have been reported to up-regulate the NGB expression highlighting the possibility to develop NGB-mediated therapeutic strategies against stroke damage and neurodegenerative diseases. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.

Poised for success: implementation of sound conditioning strategies to promote endogenous protective responses to stroke in patients

The following perspective represents our summary of questions, ideas, concerns, and recommendations expressed by speakers and discussants at the second Biennial Translational Preconditioning Workshop held in Miami in December 2011.

Neuroprotective, neurotherapeutic, and neurometabolic effects of carbon monoxide

Studies in animal models show that the primary mechanism by which heme-oxygenases impart beneficial effects is due to the gaseous molecule carbon monoxide (CO). Produced in humans mainly by the catabolism of heme by heme-oxygenase, CO is a neurotransmitter important for multiple neurologic functions and affects several intracellular pathways as a regulatory molecule. Exogenous administration of inhaled CO or carbon monoxide releasing molecules (CORM’s) impart similar neurophysiological responses as the endogenous gas. Its’ involvement in important neuronal functions suggests that regulation of CO synthesis and biochemical properties may be clinically relevant to neuroprotection and the key may be a change in metabolic substrate from glucose to lactate. Currently, the drug is under development as a therapeutic agent and safety studies in humans evaluating the safety and tolerability of inhaled doses of CO show no clinically important abnormalities, effects, or changes over time in laboratory safety variables. As an important therapeutic option, inhaled CO has entered clinical trials and its clinical role as a neuroprotective and neurotherapeutic agent has been suggested. In this article, we review the neuroprotective effects of endogenous CO and discuss exogenous CO as a neuroprotective and neurotherapeutic agent.

Training the brain to survive stroke

Background

Presently, little can be done to repair brain tissue after stroke damage. We hypothesized that the mammalian brain has an intrinsic capacity to adapt to low oxygen which would improve outcome from a reversible hypoxic/ischemic episode. Acclimation to chronic hypoxia causes increased capillarity and tissue oxygen levels which may improve the capacity to survive ischemia. Identification of these adaptations will lead to protocols which high risk groups could use to improve recovery and reduce costs.

Methods and Findings

Rats were exposed to hypoxia (3 weeks living at ½ an atmosphere). After acclimation, capillary density was measured morphometrically and was increased by 30% in the cortex. Novel implantable oxygen sensors showed that partial pressure of oxygen in the brain was increased by 40% in the normal cortex. Infarcts were induced in brain with 1 h reversible middle cerebral artery occlusions. After ischemia (48 h) behavioural scores were improved and T2 weighted MRI lesion volumes were reduced by 52% in acclimated groups. There was a reduction in inflammation indicated by reduced lymphocytes (by 27–33%), and ED1 positive cells (by 35–45%).

Conclusions

It is possible to stimulate a natural adaptive mechanism in the brain which will reduce damage and improve outcome for a given ischemic event. Since these adaptations occur after factors such as HIF-1α have returned to baseline, protection is likely related more to morphological changes such as angiogenesis. Such pre-conditioning, perhaps with exercise or pharmaceuticals, would not necessarily reduce the incidence of stroke, but the severity of damage could be reduced by 50%.

Neuroglobin, a novel target for endogenous neuroprotection against stroke and neurodegenerative disorders

Brain neurons and tissues respond to sublethal injury by activating endogenous protective pathways. Recently, following the failure of a large number of clinical trials for protective strategies against stroke that aim to inhibit a specific ischemia response pathway, endogenous neuroprotection has emerged as a more promising and hopeful strategy for development of therapeutics against stroke and neurodegenerative disorders. Neuroglobin (Ngb) is an oxygen-binding globin protein that is highly and specifically expressed in brain neurons. Accumulating evidence have clearly demonstrated that Ngb is an endogenous neuroprotective molecule against hypoxic/ischemic and oxidative stress-related insults in cultured neurons and animals, as well as neurodegenerative disorders such as Alzheimer’s disease, thus any pharmacological strategy that can up-regulate endogenous Ngb expression may lead to novel therapeutics against these brain disorders. In this review, we summarize recent studies about the biological function, regulation of gene expression, and neuroprotective mechanisms of Ngb. Furthermore, strategies for identification of chemical compounds that can up-regulate endogenous Ngb expression for neuroprotection against stroke and neurodegenerative disorders are discussed.

Mitochondrial hexokinase II (HKII) and phosphoprotein enriched in astrocytes (PEA15) form a molecular switch governing cellular fate depending on the metabolic state

The metabolic state of a cell is a key determinant in the decision to live and proliferate or to die. Consequently, balanced energy metabolism and the regulation of apoptosis are critical for the development and maintenance of differentiated organisms. Hypoxia occurs physiologically during development or exercise and pathologically in vascular disease, tumorigenesis, and inflammation, interfering with homeostatic metabolism. Here, we show that the hypoxia-inducible factor (HIF)-1-regulated glycolytic enzyme hexokinase II (HKII) acts as a molecular switch that determines cellular fate by regulating both cytoprotection and induction of apoptosis based on the metabolic state. We provide evidence for a direct molecular interactor of HKII and show that, together with phosphoprotein enriched in astrocytes (PEA15), HKII inhibits apoptosis after hypoxia. In contrast, HKII accelerates apoptosis in the absence of PEA15 and under glucose deprivation. HKII both protects cells from death during hypoxia and functions as a sensor of glucose availability during normoxia, inducing apoptosis in response to glucose depletion. Thus, HKII-mediated apoptosis may represent an evolutionarily conserved altruistic mechanism to eliminate cells during metabolic stress to the advantage of a multicellular organism.